Gibberellins are a class of plant growth regulators which are diterpenoid acids. Gibberellins are commercially produced by fermentation of a natural fungus, Gibberella fugikuroi. Gibberellins are marketed under various trade names and are commercially used on a variety of fruit orchards, vegetable crops, row crops, and ornamental crops. The predominantly used gibberellin is gibberellin acid (“GA3”).
Currently there is a strong need for methods to effectively and conveniently deliver gibberellins to the root systems of plants. Further, it is desirable to be able to deliver the gibberellin to the root system even when the root system is under standing water. An effective soil application would be desirable because it places the gibberellin in close proximity to the root system which can then efficiently uptake the gibberellin.
One issue with soil application is that when prior art formulations, such as powders, are applied to flooded crop growing areas, the gibberellin might remain on the surface of the water due to its poor wetting and low water solubility. The gibberellin might then break down due to hydrolysis before the plants' roots can absorb it.
Clay-based formulations have been used in attempts to deliver the gibberellin to the plants, as well. This method failed because the clay granules did not deliver or release the gibberellin to the soil. Further, clay based products tend to produce dust upon handling, such as when pouring, transferring or measuring them. This dust may pose health hazards.
A further issue is that it is desirable to apply low concentrations of gibberellins to flooded crop plants. Such low levels of gibberellins require large amounts of excipients or carriers which can leave residues on the plants or growing environment. In addition, the excipients or carriers could greatly increase the cost of the gibberellin product due to excessive processing and transportation costs.
Therefore, there is a need for environmentally safe, non-phytotoxic, efficacious, and economic gibberellin formulations which can be applied to the soil, including when the soil is under standing water. The improved formulations should overcome the toxicity, handling, storage, transportation, and delivery issues encountered by prior art formulations.